The goal of this program is the development and use of methodologies which adapt multiparameter analysis and sorting to solve problems in biomedical research and clincal medicine. Personnel with expertise in multiparameter cell sorting from the Department of Pathology are brought together in close collaboration with biologists and clinicians in several other departments at the University of Rochester Medical School. Topics under investigation include: 1) Methods for developing non-invasive screening procedures in genetic testing of unborn fetuses by detection and analysis of fetal cells in the maternal circulation; 2) Cytochemical studies involving the detection of differences in chromatin of resting and proliferating cells, and important problem in cancer radiation therapy and chemotherapy; 3) Categorization of B and T cell subclasses by antigen binding capacities; 4) Studies of conditionally lethal mutants to develop methods for genetic mapping; 5) Development of rapid and sensitive diagnostic procedures for autoimmune diseases using polystyrene microspheres; and 6) Studies of viral binding receptors and the differential susceptibility of human cells to viral infection. These diverse biological and clinical applications all make use of the new type of quantitative biology known as multiparameter cell sorting which is available to all projects as a multi-user facility.